Feasibility of Automotive Coatings Designed for Direct Adhesion to TPO Materials

Abstract

The discovery that adhesion to untreated nonpolar Thermoplastic PolyOlefin (TPO) could be achieved directly through olefinic color coats based on low viscosity functional liquid polymers might be considered the breakthrough for the TPO industry. The industry required the nonpolar, olefinic TPO to conform to the polar coating systems. The new paradigm suggests that the coatings should be designed for the olefinic, nonpolar TPO, therefore, eliminating surface pretreatment. The novelty of this approach is Shell's discovery that the low viscosity functional “Kraton Liquid™ Polymer” could be formulated into production of color coats, thus eliminating the need for the TPO pretreatment process. Examples of the surface treatments to enhance the adhesion between the TPO substrate and the color coat are using adhesion promoter, followed by flame and plasma treatments, and using directly paintable TPO. Based on this comparison of TPO pretreatment processes, their quality control methods, including actual or hypothetical knowledge of their adhesion mechanisms and their benefits, it is concluded that the low viscosity olefinic polymers may be feasible to be incorporated in the production pigmented color coats. A rigorous evaluation is essential before their application can be adapted in the automotive manufacturing plants, and the benefits realized.